System and method for formation detection and evaluation

ABSTRACT

A method for using markers with a drilling plan uses a first log file of a first well in order to identify and store one or more markers that have a name, a true vertical depth (TVD) and a waveform. Second well log data generated while a second well is being drilled is monitored in real time. The second well log data is compared to the one or more markers to located a match to at least one marker in a predetermined TVD range. An estimated TVD value and an uncertainty range value are assigned to each of the at least one planned marker. When a matching marker is located for one of the one or more markers in the predetermined TVD range a report is generated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/332,531, filed Jul. 16, 2014, entitled SYSTEM AND METHOD FORFORMATION DETECTION AND EVALUATION, now U.S. Pat. No. 8,977,501, issuedMar. 10, 2015 which is a continuation of U.S. patent application Ser.No. 14/186,470, filed Feb. 21, 2014, entitled SYSTEM AND METHOD FORFORMATION DETECTION AND EVALUATION, now U.S. Pat. No. 8,818,729, issuedAug. 26, 2014, which claims benefit of expired U.S. Provisional Ser. No.61/838,689, filed on Jun. 24, 2013, and entitled SYSTEM AND METHOD FORFORMATION DETECTION, the specifications of which are incorporated hereinby reference in their entirety.

TECHNICAL FIELD

The following disclosure relates to directional and conventionaldrilling.

BACKGROUND

Drilling a borehole for the extraction of minerals has become anincreasingly complicated operation due to the increased depth andcomplexity of many boreholes, including the complexity added bydirectional drilling. Drilling is an expensive operation and errors indrilling add to the cost and, in some cases, drilling errors maypermanently lower the output of a well for years into the future.Current technologies and methods do not adequately address thecomplicated nature of drilling. Accordingly, what is needed are a systemand method to improve drilling operations.

SUMMARY

The present invention, as disclosed and described herein, in one aspectthereof, comprises a method for using markers with a drilling plan usesa first log file of a first well in order to identify and store one ormore markers that have a name, a true vertical depth (TVD) and awaveform. Second well log data generated while a second well is beingdrilled is monitored in real time. The second well log data is comparedto the one or more markers to located a match to at least one marker ina predetermined TVD range. An estimated TVD value and an uncertaintyrange value are assigned to each of the at least one planned marker.When a matching marker is located for one of the one or more markers inthe predetermined TVD range a report is generated.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding, reference is now made to thefollowing description taken in conjunction with the accompanyingDrawings in which:

FIG. 1A illustrates one embodiment of an environment within whichvarious aspects of the present disclosure may be implemented;

FIG. 1B illustrates one embodiment of a drilling system that may be usedwithin the environment of FIG. 1A;

FIG. 1C illustrates one embodiment of a computer system that may be usedwithin the environment of FIG. 1A and/or with the drilling system ofFIG. 1B;

FIG. 2 illustrates a flow chart of one embodiment of a method that maybe used to create baseline markers, associate the created baselinemarkers with planned markers, and scan for the planned markers duringdrilling;

FIG. 3 illustrates a flow chart of one embodiment of a method that maybe used to create baseline markers;

FIG. 4 illustrates one embodiment of a log file that may be used by themethod of FIG. 3;

FIG. 5 illustrates one embodiment of a baseline marker that may becreated from the log file of FIG. 4;

FIG. 6 illustrates one embodiment of a representation of the baselinemarker of FIG. 5;

FIG. 7 illustrates a flow chart of one embodiment of a method that maybe used to create the representation of FIG. 6;

FIG. 8 illustrates one embodiment of a graphical user interface that maybe used to interact with the method of FIG. 4;

FIG. 9 illustrates a flow chart of one embodiment of a method that maybe used to create planned markers and associate them with baselinemarkers;

FIG. 10 illustrates one embodiment of a graphical user interface thatmay be used to interact with the method of FIG. 9;

FIG. 11 illustrates a flow chart of one embodiment of a method that maybe used to parse log data and identify planned markers;

FIG. 12A illustrates a flow chart of one embodiment of a more detailedexample of the flow chart of FIG. 11;

FIG. 12B illustrates a flow chart of one embodiment of a more detailedexample of one step of the flow chart of FIG. 12A;

FIG. 12C illustrates a flow chart of one embodiment of a more detailedexample of one step of the flow chart of FIG. 12A;

FIGS. 13A-13D illustrate diagrams of embodiments of a referencefingerprint and candidate fingerprints that may be obtained from anuncertainty region and compared against the reference fingerprint; and

FIG. 14 illustrates one embodiment of a graphical user interface thatmay report information from the method of FIG. 11 and/or the method ofFIGS. 12A-12C and allow a modification to be made.

DETAILED DESCRIPTION

Referring now to the drawings, wherein like reference numbers are usedherein to designate like elements throughout, various views andembodiments of a system and method for detecting markers within aformation are illustrated and described, and other possible embodimentsare described. The figures are not necessarily drawn to scale, and insome instances the drawings have been exaggerated and/or simplified inplaces for illustrative purposes only. One of ordinary skill in the artwill appreciate the many possible applications and variations based onthe following examples of possible embodiments.

Referring to FIG. 1A, one embodiment of an environment 100 isillustrated with a formation 102 having a surface 104. A borehole 106 isto be drilled or is being drilled within the formation 102 by a drillingrig 108. A drilling plan has been formulated to drill the borehole 106to a true vertical depth (TVD) 110. The borehole 106 is to extendthrough strata layers 112A, 112B and 114A, 114B stop in layer 116A, 116Band not reach underlying layers 118A, 118B and 120A, 120B. Layerboundary 113 separates layers 112A, 112B and 114A, 114B layer boundary115 separates layers 114A, 114B and 116A, 116B layer boundary 117separates layers 116A, 116B and 118A, 118B and layer boundary 119separates layers 118A, 118B and 120A, 120B. A fault 122 has shifted aportion of each layer downwards. Accordingly, the borehole 106 islocated in non-shifted layer portions 112A-120A, while portions112B-120B represent the shifted layer portions. Although not shown, itis understood that the borehole 106 may extend past the fault 122.

The borehole 106 may be directed to a target area 124 positioned in thelayer 116A, 116B. The target area 124 may be a subsurface point orpoints defined by coordinates or other markers that indicate where theborehole 106 is to end or may simply define a depth range within whichthe borehole 106 is to remain (e.g., the layer 116A, 116B itself). It isunderstood that the target area 124 may be any shape and size, and maybe defined in any way. Accordingly, the target area 124 may represent anendpoint of the borehole 106 or may extend as far as can berealistically drilled. For example, if the drilling includes ahorizontal component and the goal is to follow the layer 116A, 116B asfar as possible, the target may simply be the layer 116A, 116B itselfand drilling may continue until a limit is reached, such as a propertyboundary or a physical limitation to the length of the drillstring.

One or more existing wells 126 may be present in the environment 100.The existing well 126 may be an offset well or may be another well thatis located relatively close to the planned borehole 106. Formationinformation (e.g., gamma logs) obtained from the well 126 may be used inplanning the borehole 106, as well as for purposes of evaluating thedrilling plan for the borehole 106 during drilling. It is understoodthat the location of the well 126 relative to the borehole 106 mayaffect the relevancy of the formation information obtained from theborehole 106. For example, the depths of the various layer boundaries113, 115, 117, and 119 vary depending on the location of the well 126.Generally, the closer the well 126 is to the borehole 106, the morecorrelation there will be in the formation characteristics of the twowells. However, some exceptions may apply, such as two wells on oppositesides of the fault line 122.

In the present embodiment, the formation information includes gammaradiation readings obtained from gamma logs, which provide a record ofthe radioactivity of earth materials relative to depth. Accordingly,gamma logs may be used to provide some indication as to the currentlocation of the borehole 106 (e.g., the BHA 149 of FIG. 1B) relative tothe various layer boundaries 113, 115, and 117 and layers 112A, 112B,114A, 114B and 116A, 116B and may also provide information as to theapproximate location of the BHA within a particular layer due tovariations in radioactivity within the layer itself.

It is understood that while gamma logs containing gamma radiationreadings are used for purposes of example, the present disclosure is notlimited to gamma logs and other types of information, includingformation information and/or drilling operational parameters indicativeof changes, may be used in the various embodiments described herein inaddition to, or as an alternative to, gamma information. For example,information pertaining to resistivity, porosity, pressure, neutrondensity, rate of penetration (ROP), and/or mechanical specific energy(MSE) may be used. Generally, the information used needs to provideenough detail to be useful in making real time or near real timeadjustments to the drilling plan. Accordingly, the resolution of theinformation may affect the accuracy of the processes described herein.

Referring to FIG. 1B, an environment 130 illustrates one embodiment of aportion of the environment 100 of FIG. 1A in greater detail. In thepresent example, the environment 100 includes a derrick 132 on thesurface 104. The derrick 132 may be part of the drilling rig 108 of FIG.1A. The derrick 132 includes a crown block 134. A traveling block 136 iscoupled to the crown block 134 via a drilling line 138. In a top drivesystem (as illustrated), a top drive 140 is coupled to the travelingblock 136 and provides the rotational force needed for drilling. A saversub 142 may sit between the top drive 140 and a drill pipe 144 that ispart of a drill string 146. The top drive 140 rotates the drill string146 via the saver sub 142, which in turn rotates a drill bit 148 of abottom hole assembly (BHA) 149 in the borehole 106 in the formation 102.A mud pump 152 may direct a fluid mixture (e.g., mud) 153 from a mud pitor other container 154 into the borehole 106. The mud 153 may flow fromthe mud pump 152 into a discharge line 156 that is coupled to a rotaryhose 158 by a standpipe 160. The rotary hose 158 is coupled to the topdrive 140, which includes a passage for the mud 153 to flow into thedrill string 146 and the borehole 106. A rotary table 162 may be fittedwith a master bushing 164 to hold the drill string 146 when the drillstring is not rotating.

Sensing, detection, and/or evaluation functionality may be incorporatedinto a downhole tool 166 (which may be located in one or more positionsalong the drill string), BHA 149, or may be located elsewhere along thedrill string 146. For example, gamma radiation sensors may be includedin the downhole tool 166 and/or elsewhere along the drill string 146.

In some embodiments, formation detection and evaluation functionalitymay be provided via a control system 168 on the surface 104. The controlsystem 168 may be located at the derrick 132 or may be remote from theactual drilling location. For example, the control system 168 may be asystem such as is disclosed in U.S. Pat. No. 8,210,283 entitled SYSTEMAND METHOD FOR SURFACE STEERABLE DRILLING, filed on Dec. 22, 2011, andissued on Jul. 3, 2012, which is hereby incorporated by reference in itsentirety. Alternatively, the control system 168 may be a stand-alonesystem or may be incorporated into other systems at the derrick 132. Thecontrol system 168 may receive formation information via a wired and/orwireless connection (not shown). In some embodiments, the control system168 may use the evaluation functionality to provide convergence plansand/or other corrective measures as disclosed in U.S. patent applicationSer. No. 13/530,298, now U.S. Pat. No. 8,596,385, entitled SYSTEM ANDMETHOD FOR DETERMINING INCREMENTAL PROGRESSION BETWEEN SURVEY POINTSWHILE DRILLING, filed on Jun. 22, 2012, and issued on Dec. 3, 2013,which is hereby incorporated by reference in its entirety. Some or allof the control system 168 may be positioned in the downhole tool 166 ormay communicate with a separate controller in the downhole tool 166.

Referring to FIG. 1C, one embodiment of a computer system 180 isillustrated. The computer system 180 is one possible example of a systemcomponent or device such as the control system 168 of FIG. 1B or aseparate system used to perform the various processes described herein.In scenarios where the computer system 180 is on-site, such as withinthe environment 100 of FIG. 1A and/or the environment 130 of FIG. 1B,the computer system may be contained in a relatively rugged,shock-resistant case that is hardened for industrial applications andharsh environments. It is understood that downhole electronics may bemounted in an adaptive suspension system or another type of dampeningsystem.

The computer system 180 may include a central processing unit (“CPU”)182, a memory unit 184, an input/output (“I/O”) device 186, and anetwork interface 188. The components 182, 184, 186, and 188 areinterconnected by a transport system (e.g., a bus) 190. A power supply(PS) 192 may provide power to components of the computer system 180 viaa power transport system 194 (shown with data transport system 190,although the power and data transport systems may be separate).

It is understood that the computer system 180 may be differentlyconfigured and that each of the listed components may actually representseveral different components. For example, the CPU 182 may actuallyrepresent a multi-processor or a distributed processing system; thememory unit 184 may include different levels of cache memory, mainmemory, hard disks, and remote storage locations; the I/O device 186 mayinclude monitors, keyboards, and the like; and the network interface 188may include one or more network cards providing one or more wired and/orwireless connections to a network 196. Therefore, a wide range offlexibility is anticipated in the configuration of the computer system180.

The computer system 180 may use any operating system (or multipleoperating systems), including various versions of operating systemsprovided by Microsoft (such as WINDOWS®), APPLE® (such as Mac® OS X®),UNIX®, and LINUX®, and may include operating systems specificallydeveloped for handheld devices, personal computers, and serversdepending on the use of the computer system 180. The operating system,as well as other instructions (e.g., software instructions forperforming the functionality described in various embodiments describedherein) may be stored in the memory unit 184 and executed by theprocessor 182. For example, the memory unit 184 may include instructionsfor performing the various methods and control functions disclosedherein.

The network 196 may be a single network or may represent multiplenetworks, including networks of different types. For example, thenetwork 196 may include one or more cellular links, data packet networkssuch as the Internet, local area networks (LANs), and/or wide local areanetworks (WLAN), and/or Public Switched Telephone Networks (PSTNs).Accordingly, many different network types and configurations may be usedto couple the computer system 180 to other components of the environment100 of FIG. 1A, the environment 130 of FIG. 1B, and/or to other systemsnot shown (e.g., remote systems).

Referring to FIG. 2, one embodiment of a method 200 illustrates aprocess that may be used to create baseline markers from formationinformation obtained from an existing well, associate one or moreplanned markers in a drilling plan with a baseline marker, identifyplanned markers from formation information obtained while drilling a newwell, and determine whether to modify the drilling plan based ondifferences between the baseline markers and the planned markers. In thepresent example, gamma logs have been obtained from the well 126 of FIG.1A and baseline markers from the gamma logs are used in creating orrefining a drilling plan for the borehole 106. The baseline markers mayalso be used in evaluating the drilling plan during the drillingprocess.

In step 202, baseline markers are created from gamma logs obtained fromthe existing well 126. The baseline markers correspond to waveformsrepresenting detected gamma values that are identifiable anddistinguishable from surrounding gamma values in the logs. For example,a waveform representing a relatively significant spike in the gamma logthat is surrounded by lower level readings may be selected as a baselinemarker. It is understood that a baseline marker need not be a particularshape or amplitude, but may be selected at least in part based on itsrelation to surrounding readings.

The selection process may be performed manually by a geologist oranother individual able to identify log information that would make anacceptable baseline marker (e.g., using a computer system to highlightsuch information and save it as a baseline marker) or may be performedautomatically by a computer system. In cases where the computer systemautomatically identifies and saves baseline markers, a person may verifyand/or modify the baseline markers at a later time. Once a particularportion of a log is identified and selected to serve as a baselinemarker, the information is saved in a marker archive with correspondingdata, such as name, TVD, and shape. In the present embodiment, themarker archive corresponds to the well 126, but it is understood thatother storage criteria may be used in categorizing a baseline marker.For example, a baseline marker may be associated with a particulargeographic area and/or a formation layer rather than with a particularwell.

In step 204, planned markers are created for the drilling plan. Eachplanned marker is associated with a baseline marker from a markerarchive, which in this example is the marker archive of the well 126. Itis noted that the marker archive for the well 126 may have been createdat some point in the past (e.g., for another well) and may include theoriginal baseline markers, modified baseline markers, and/or addedbaseline markers. Accordingly, the marker archive may not be fixed, butmay be refined over time in some cases. Information for each plannedmarker is entered, such as estimated TVD and an uncertainty range (e.g.,plus or minus thirty feet) that may aid in minimizing or eliminatingfalse positives. For example, if the uncertainty range is plus or minusthirty feet, there will be an uncertainty region of sixty feet. As willbe described later, the uncertainty region may be used when scanning forplanned markers as the borehole 106 is being drilled. While plannedmarkers are created in step 204 in the present embodiment, it isunderstood that planned markers may be obtained using different methodsin other embodiments, such as retrieving the planned markers from adatabase or automatically calculating information for a planned marker(e.g., location) as needed.

In step 206, which occurs during drilling until all markers have beenprocessed, gamma logs are obtained and analyzed as further illustratedin sub-steps 208, 210, and 212. For example, in step 208, the gamma logsare scanned for planned markers created in step 204. The gamma logs maybe obtained in real time or near real time as the formation informationis gathered by downhole sensors and relayed to the surface and the logscanning may also occur in real time or near real time. In step 210, anidentified planned marker is reported. This reporting may be done inreal time or near real time. The real time or near real time aspect ofthe information gathering, scanning, and reporting enables differencesbetween the drilling plan and the actual drilled borehole to beidentified relatively quickly, thereby minimizing the time needed tocorrect for errors.

In step 212, a decision may be made to adjust the drilling plan or tolet drilling continue without adjustment. For example, if the plannedmarker is reported as being five feet lower than expected, the reportmay be reviewed and a decision may be made that no change is needed.However, if the planned marker is reported as being twenty feet lowerthan expected, the plan may be changed to compensate for thisdifference. For example, the TVD and/or the bed dip may be modified. Itis understood that this is only an example and that many differentfactors may influence the decision on whether the plan is to be changedafter the TVD of a planned marker is identified. This decision may occurrelatively quickly following the report in order to correct the drillingplan as soon as an undesirable deviation is detected. Assuming thatfactors such as the timing of the report, who is monitoring the report,the authority of the person or persons monitoring the report, and thecorrectional capabilities of the drilling process enable corrections tobe made relatively rapidly, the correction may be made before the nextplanned marker is found.

It is understood that processing a marker in step 206 may includeskipping that marker. For example, if a marker is not identified, thatmarker may be skipped. A marker that coincides with a fault or anothergeological irregularity may simply not exist or may be so altered as tobe unrecognizable. If a marker is not located and yet not skipped, thesystem would continue looking for that marker and miss the next marker.Such skipping may be automatic (e.g., skip a marker that is not foundwithin fifty feet of its estimated depth) or may be manually controlled(e.g., notify a user that a marker has not been found and let the userdecide whether to keep searching for the marker or skip it).

Referring to FIG. 3, one embodiment of a method 300 illustrates aprocess that may be used to identify suitable baseline markers from anexisting well and store those baseline markers for later use. The method300 may be entirely automatic (e.g., computer controlled) or may bebased on user input (e.g., the selection of particular waveforms).

In step 302, information is identified from a log (e.g., a gamma logfrom the well 126 of FIG. 1A) that meets one or more criteria for abaseline marker. The criteria may include a minimum width and/orrelative amplitude for a gamma spike, shape limitations (e.g., a spikemay need to be relatively sharp rather than a gentle slope), or may needto be a shape that is readily distinguishable from other shapes. It isunderstood that the criteria may be relative in that a particular spikemay be suitable as a baseline marker in one part of the log, but not inanother part of the log. For example, a spike that is in close proximityto one or more other spikes of similar amplitude may not be suitable fora baseline marker, but a spike that is relatively isolated and/or has asignificantly larger magnitude may be suitable.

With additional reference to FIG. 4, one embodiment of a portion of agamma log 402 is illustrated. The gamma log 402 includes a graph 404that visually illustrates a series of gamma readings using line 406 torepresent gamma radiation values and corresponding depths. In thepresent example, a portion 408 of the gamma log 402 has been highlightedfor use as a baseline marker, as will be described with respect to thenext step of FIG. 3.

Referring again to FIG. 3, in step 304, a baseline marker is createdfrom the selected portion of the gamma log. For example, referring toFIG. 5, one embodiment of a chart 502 provides a representation of abaseline marker 504. The baseline marker 504 is shown against an axisrepresenting the gamma value and an axis representing the distance(e.g., width) of the baseline marker 504. It is understood that thisinformation is derived from the gamma log 402 of FIG. 4, with the widthbeing calculated based on the depth at which the particular points ofthe baseline marker 504 appear on the gamma log 402. It is furtherunderstood that the baseline marker 504 may be an exact match of thewaveform from the gamma log 402 or may be a waveform representation(e.g., may be based on the waveform but not an exact representation).

With additional reference to FIGS. 6 and 7, embodiments of a diagram 600(FIG. 6) and method 700 (FIG. 7) illustrate a waveform representation ofa baseline marker (e.g., the baseline marker 504 of FIG. 5) and how sucha waveform representation may be constructed. It is understood that thewaveform representation is one example of a mathematical representation(e.g., a fingerprint) of the baseline marker 504. It is furtherunderstood that this is only one example of how fingerprinting may occurfor a baseline marker and that many other representations may be used.In addition, while described with respect to the method 300 of FIG. 3,it is understood that the representation may be constructed as part ofone or more other processes, such as during the creation of fingerprintsfor new wells as will be described later.

As illustrated in FIG. 6, in the present example, the waveformrepresentation includes a line 602 that represents the left side averageof the baseline marker 504. A line 604 represents the peak heightrelative to the left side average. A line 606 represents the right sideaverage relative to the left side average. A line 608 represents thewidth of the baseline marker. The width may vary based on the portion ofthe gamma log selected as the baseline marker 504. The position of theline 604 with respect to the line 608 represents the location of thepeak index relative to the width of the baseline marker. It isunderstood that this waveform representation is primarily constructedusing relative values to meet the challenge of identifying a plannedmarker even when changes have occurred in amplitude, width, shape,and/or other characteristics.

In general, measured amplitudes may be handled carefully due todifferences in sensors. For example, a comparison between the recordedamplitude of a baseline marker and the recorded amplitude of a plannedmarker cannot be relied upon when the gamma radiation sensors are notcalibrated relative to one another. Accordingly, while amplitude may beused in the selection of baseline markers and the later comparison ofbaseline markers and planned markers, the present disclosure generallyuses relative amplitude (e.g., relative to the left side average) ratherthan absolute amplitude. In embodiments where the sensors are known tobe calibrated relative to one another and/or where the recorded sensorresults can be adjusted to account for sensor differences, absoluteamplitude may be relied upon more heavily.

It is understood that a waveform representation may have many differentcharacteristics. For example, a multi-peak waveform representation maybe used (with or without averaging the peaks). This may be particularlyuseful in build and lateral sections of the borehole where the waveformis rotated rather than being vertical. This may also be useful when thelog file can be read in two directions (e.g., forward and backward) ashaving at least two peaks to read may provide insight into whichdirection the log file is being read since the order in which the peaksare identified will be different depending on the direction in which thelog file is read.

While the present disclosure is described using vertical sections of theborehole 106, it is understood that the concepts described herein mayalso be applied to horizontal and build sections. Although somedifferences may exist between vertical, horizontal, and build sections,the basic process of using baseline markers and planned markers toassess the accuracy of drilling in real time or near real time and tomake corrections if needed remains the same.

As illustrated in FIG. 7, the method 700 may be used to construct thewaveform representation of FIG. 6. In step 702, the left side average iscalculated. It is understood that the left side average may be usedbecause the gamma log generally follows a pattern of descending depth.This means that the left part of the log (e.g., the “top” of the logrepresenting shallower depths) will be scanned first during real time ornear real time scanning Accordingly, the first part of a baseline markerto be scanned will typically be the left side of the baseline marker. Itis understood that this process may be performed differently (e.g.,scanning from right to left) and would still be covered by the currentdescription, but scanning from left to right (e.g., shallower depths todeeper depths) is the general process used for this example.

The left side average may be calculated in many ways. For example, theleft side average may be a single average value from the left side ofthe marker to the peak. In other embodiments, there may be multipleaverages. For example, a stair step or multi-peak average may be used.The right side average may be calculated in the same way as the leftside average or in a different way. Furthermore, the averaging processmay vary depending on the particular shape and/or width of the portionof the waveform being averaged.

In step 704, the peak height and the right side average are calculatedrelative to the left side average. For example, continuing the exampleof FIG. 5, the left side average may be a gamma reading of 100. The peakheight is 135 and the right side value is 80. The peak height relativeto the left side average would be 1.35. The right side average relativeto the left side would be 0.80.

In step 706, the width of the baseline marker is calculated and thelocation of the peak height relative to the width is calculated. Thewidth may be calculated by subtracting the TVD of the right side fromthe TVD of the left side. The location of the peak height may then beidentified. For example, if the width is forty-one feet, the location ofthe peak can be calculated as whatever value matches the location of thepeak height. It is noted that the use of relative values and averagesenables a possible match between two waveforms to be described in termsof a percentage, as an exact match is unlikely to occur. For example,the use of relative values addresses discrepancies that might otherwiseexist between two waveforms due to sensors not being calibrated withrespect to one another, as well as formation to formation discrepancies.A more detailed example of this process is discussed later.

Referring again to FIG. 3, in step 306, the baseline marker andcorresponding information (e.g., name and waveform representation (asthe actual waveform and/or as calculated representation values) arestored in the baseline marker archive corresponding to the well withwhich the gamma log is associated. In step 308, a determination may bemade as to whether the method 300 has finished (e.g., whether additionalbaseline markers are to be selected from the gamma log). If thedetermination indicates that the method 300 is not finished, the methodreturns to step 302. If the determination indicates that the method 300is finished, the method ends.

Referring to FIG. 8, one embodiment of a GUI 800 illustrates aninterface that may be used to retrieve a log file and add, edit, ordelete baseline markers. It is understood that the GUI 800 is forpurposes of example and that many different GUIs may be used to providesome or all of the functionality shown with the GUI 800. In the presentexample, the GUI 800 includes a file selection panel 802, a markerselection panel 804, a quality display panel 806, and a gamma log panel808.

In operation, a user may create or edit a marker archive file usingsection 802. In the present example, the marker archive file is “OffsetWell 126 archive.txt,” which corresponds to the offset well 126 of FIG.1A. A corresponding offset well may be associated with the offset wellif that has not already been done. The user may then highlight (e.g.,using a mouse, keyboard, and/or other interfaces) one or more sectionsof the gamma log. As these are highlighted, they are added to the markerselection panel 804. For example, the illustrated portion of the gammalog includes four selected portions 810, 812, 814, and 816. The markerselection panel 804 illustrates eight markers 818, 820, 822, 824, 826,828, 830, and 832, each of which has a name, a start depth, and an enddepth. The start depth and end depth may be automatically entered basedon the corresponding selected portion. For purposes of illustration, theselected portion 810 corresponds to marker 820, the selected portion 812corresponds to marker 822, the selected portion 814 corresponds tomarker 824, and the selected portion 816 corresponds to marker 826.

The quality display panel 806 contains quality indicators thatillustrate a quality level of the currently selected marker. The qualitylevel represents the strength of the selected marker. For example, thequality display panel 806 may include a graph that illustrates aqualitative analysis of the difference between the right side averageand the left side average, as well as the difference between the leftside average and the peak. The selected widths are also illustrated.Using this feedback, a user can select the marker differently tostrengthen these attributes.

In the present example, the quality display panel 806 plots left, right,and peak values against a vertical axis measured in API (the unit ofradioactivity used for gamma logs) and a horizontal axis measured inwidth. The width may be represented as TVD in some embodiments. It isnoted that in offset logs, the TVD generally equals the measured depthunless the log is a TVD converted log. A messages section may be used tocomment on the quality of the currently selected marker. For example,the current message indicates that the peak value is small relative tothe left side value.

Accordingly, using the GUI 800, a user can scroll through a gamma log,select portions of the gamma log, and save those portions as baselinemarkers. In addition, previously saved baseline markers can be edited ordeleted.

Referring to FIG. 9, one embodiment of a method 900 illustrates aprocess that may be used to create planned markers for a drilling planfor a new well and associate each planned marker with a correspondingbaseline marker from an existing well. For example, using theenvironment 100 of FIG. 1A, a drilling plan is being created or revisedfor the borehole 106. Baseline markers have been created for the offsetwell 126 and those baseline markers are available for use in theplanning of the borehole 106. While there may be variations between thebaseline markers and the planned markers once the planned markers areactually located in the borehole 106 (e.g., differences in TVD, gammalevels, and/or shape) due to differences between the two locationswithin the formation 102, the baseline markers provide at least someknowledge of where the planned markers may appear.

In step 902, a marker name is created for a new planned marker. In step904, the planned marker is associated with a baseline marker from themarker archive of the offset well 126. For example, assume that aplanned marker will likely occur at the layer boundary 113. This plannedmarker may then be associated with a baseline marker from the offsetwell 126 that is located at the layer boundary 113.

In step 906, an estimated depth, an uncertainty region, and an expectedvertical section may be provided for the planned marker (e.g., enteredor imported from a database or other memory). The estimated depth may bebased on other information, such as general knowledge of the formation102 (e.g., whether the boundary layer 113 is level, rising, or fallingbetween the offset well and the planned borehole 106). It is understoodthat such information may be gathered from other offset wells, otherwells, and/or other types of survey information, and may be gatheredboth locally and over a relatively large region. For example, databasesthat may contain such information are described previously incorporatedU.S. Pat. No. 8,210,283 entitled SYSTEM AND METHOD FOR SURFACE STEERABLEDRILLING.

The uncertainty region provides an estimated region in which the plannedmarker may be found (e.g., plus or minus twenty feet). The expectedvertical section provides a reference to the drilling plan and morespecifically identifies a particular vertical section of the plan inwhich the planned marker is likely to be located. It is understood thatmore or less information may be provided. For example, the expectedvertical section may be omitted in some embodiments.

Further adjustments may be made if needed. For example, if the waveformrepresentation is calculated based on the appearance of a waveform in avertical section, but it is estimated that the marker will be identifiedin a build section in the current borehole, then the waveformrepresentation must likely be modified or it will be missed.Accordingly, compensations may be made based on factors such as where aparticular waveform representation is expected to be located in thecurrent borehole.

In step 908, a determination may be made as to whether the process hasfinished (e.g., whether there are more planned markers to create). Ifthe process is not finished, the method 900 returns to step 902. If theprocess is finished, the method 900 ends.

Referring to FIG. 10, one embodiment of a GUI 1000 illustrates aninterface that may be used to create and/or edit planned markers for adrilling plan. It is understood that the GUI 1000 is for purposes ofexample and that many different GUIs may be used to provide some or allof the functionality shown with the GUI 1000. In the present example,the GUI 1000 includes a geo plan selection panel 1002, a geo planparameters panel 1004, and a well plan selection panel 1006.

In operation, a user may create or edit a geo plan for the borehole 106via text box 1008 and associated control buttons. In the presentexample, the geo plan is named “Current Well Geo Plan Full.txt.” Theuser may also select a marker archive as illustrated by text box 1010.In the present example, the marker archive is the “Offset Well 126archive.txt” described with respect to FIG. 8. A formation dip angle maybe entered in text box 1012. In some embodiments, a dip angle may besuggested for the user based on identified trends, current/next markers,and/or similar factors. A well plan may be selected from the well planselection panel 1006 from any of multiple sources, such as a Log ASCIIStandard (LAS) file, a global database, or a local database. It isunderstood that the geo plan, marker archive, and/or well plan may bepulled from storage, either local or online (e.g., from a remotelyaccessible database or a server cloud).

For purpose of example, the geo plan parameters panel 1004 illustrateseight planned markers 1014, 1016, 1018, 1020, 1022, 1024, 1026, and1028. Each planned marker corresponds to one of the baseline markers818, 820, 822, 824, 826, 828, 830, and 832 of FIG. 8, with plannedmarker 1014 corresponding to baseline marker 818, planned marker 1016corresponding to baseline marker 820, planned marker 1018 correspondingto baseline marker 822, planned marker 1020 corresponding to baselinemarker 824, planned marker 1022 corresponding to baseline marker 826,planned marker 1024 corresponding to baseline marker 828, planned marker1026 corresponding to baseline marker 830, and planned marker 1028corresponding to baseline marker 832.

Each planned marker 1014, 1016, 1018, 1020, 1022, 1024, 1026, and 1028is also associated with an estimated TVD, an uncertainty range, and anestimated vertical section. For example, the planned marker 1022 hasbeen assigned an estimated TVD of 8179 feet with an uncertainty range ofplus or minus twelve feet. It is expected to appear in vertical sectionfive hundred and fifteen of the drilling plan. Accordingly, using thecorresponding baseline marker 826 of FIG. 8 taken from the portion 816,a gamma log of the borehole 106 may be scanned to find the plannedmarker 1022. It is noted that the estimated vertical section is notneeded if the log is converted to Kelly bushing TVD (KBTVD) references.

The estimated TVD, uncertainty range, and/or the estimated verticalsection may provide benchmarks for determining the accuracy of the wellplan and/or may be used to focus more detailed scanning on a particularsection. For example, rather than scan each foot (or whatever resolutionis selected) for a fingerprint, the system may skip or more rapidly scanportions of the gamma log that are unlikely to contain planned markersand focus on portions of the gamma log more likely to contain suchmarkers.

Referring to FIG. 11, one embodiment of a method 1100 illustrates aprocess that may be used to scan a log for planned markers. In thepresent example, the log is a gamma log from the borehole 106 of FIG.1A, but it is understood that other types of logs may be used.

In step 1102, log data collected as the borehole 106 is drilled isparsed. The parsing may be performed in many different ways, includingscanning the log file at each foot or using another defined resolutionincrement, scanning for an uncertainty section, scanning for a verticalsection, and/or scanning using other parameters. For example, scanningfor the planned marker 1022 (FIG. 10) may involve rapidly scanning to8167 feet (i.e., the planned TVD of 8179 minus the uncertainty range oftwelve feet) and then examining the log file more closely for theplanned marker. In step 1104, the best fingerprint match for the plannedmarker is identified for the uncertainty region. For example, there maybe multiple matches or at least multiple possible matches, and themethod 1100 may select the best match.

In step 1106, a determination may be made as to whether the process hasfinished (e.g., whether more markers remain to be found). If the processis not finished, the method 1100 returns to step 1102. If the process isfinished, the method 1100 ends.

Referring to FIG. 12A, one embodiment of a method 1200 illustrates amore detailed example of the method 1100 of FIG. 11. In step 1202, logdata is parsed to identify an uncertainty region. In step 1204, adetermination may be made as to whether an uncertainty region has beenfound. If no uncertainty region has been found, the method 1200 returnsto step 1202. If an uncertainty region has been found, the method 1200continues to step 1205. In step 1205, weights are assigned to theplanned marker.

In step 1206, a fingerprint is made of the current window of theuncertainty region. For example, if the planned marker is twenty feetwide, the current window may be a twenty foot window. The system wouldmake a fingerprint of this window (as described previously).

In step 1208, the fingerprint of the current window is compared to theplanned marker's fingerprint. In step 1210, a confidence value iscalculated based on the comparison of step 1208. In step 1212, adetermination is made as to whether the current fingerprint is a newcandidate based on the TVD location of the peak. If the currentfingerprint is a new candidate, the method 1200 adds the candidate to alist of candidates in step 1214 before moving to step 1216. If thecurrent fingerprint is not a new candidate, the method 1200 continues tostep 1216 without adding to the candidate list.

In step 1216, a determination may be made as to whether the method 1200is done with the current uncertainty region. If the method 1200 is notdone with the uncertainty region, the method 1200 increments the windowin step 1218 and returns to step 1206. For example, if the window has aone foot resolution, the window's position will be incremented by onefoot (e.g., the window will move forward one foot). If the method 1200is done with the uncertainty region, the method 1200 moves to step 1220,where the list of candidates may be reported. This enables a user toreview and select a best match from all possible candidates. In someembodiments, the list may be ranked based on the level of confidenceand/or other criteria.

In step 1222, a determination may be made as to whether the process hasfinished (e.g., whether more of the log is to be scanned). If theprocess is not finished, the method 1200 returns to step 1202. If theprocess is finished, the method 1200 ends.

Referring to FIG. 12B, a more detailed embodiment of step 1205 of FIG.12A is illustrated. As described previously, the best match between areference marker and the current window in the active gamma log isneeded. To accomplish this, a fingerprint matching process is used toturn gamma samples into fingerprints to improve the matching successrate. This is expressed as a multistep approach in FIG. 12B as follows.

The fingerprint matching process compares attributes between twofingerprints (e.g., a reference fingerprint and a candidate fingerprint)and produces a score based on the comparison. The fingerprint matchingprocess considers three primary attributes in the comparison offingerprints and provides their relative weights in the final score asfollows:

-   PIW: 0.5-   PRD: 0.2-   RRD: 0.3    where PIW=peak index weight, PRD=peak relative distance, and    RRD=right relative distance. It is understood that other values may    be used for relative weighting and the provided values are only for    purposes of example. Prior to scanning an uncertainty region, the    fingerprint matching process saves the relative weights of the    reference fingerprint.

In step 1230, the weight is set for the position of the peak relative tothe width. For example, if a fingerprint has a width of ten (10) and thepeak is in index five (5), then the highest match will occur if a samplehas its peak at index five. Each index location further from the peakindex will have a lower factor (e.g., indexes 4, 3, 2, and 1 would havesuccessively lower factor values). This is expressed as follows:lc=max(rc,ltc)  (Equation 1)pif_(ref)=100.0<(lc+1)  (Equation 2)where lc=largest count, rc=right count, ltc=left count, andpif_(ref)=peak index factor of the reference fingerprint.

In step 1232, the weight is set for the height of the peak relative tothe left side average. For example, if the left average is 80 API andthe peak is 120 API, then the peak relative distance is 0.5. This isexpressed asprd_(ref)=(pd/la)−1.0  (Equation 3)where prd_(ref)=peak relative distance of the reference fingerprint,pd=peak distance of the relative fingerprint, and la=left side averageof the relative fingerprint.

In step 1234, the weight is set for the ratio of the right side averagerelative to the left side. For example, if the left average is 80 APIand the right average is 60 API, then the right relative distance is−0.25. This is expressed asrrd_(ref)=(ra/la)−1.0  (Equation 4)where ra=right side average of the reference fingerprint andrrd_(ref)=right side relative distance to the left side average of thereference fingerprint.

Referring to FIG. 12C, a more detailed embodiment of step 1208 of FIG.12A is illustrated. When a candidate fingerprint (also referred toherein as a “current” fingerprint) is created from the current window ofgamma data in the uncertainty region, a score is computed when thecandidate fingerprint is compared against the reference fingerprint. Tocompute the score, the fingerprint matching process must first determinethe match value of each attribute of the candidate fingerprint. This isexpressed as a multistep approach in FIG. 12C as follows.

In step 1240, the current peak index factor (pif_(cur)) as comparedagainst the reference (pif_(ref)) is calculated, which is expressed aspif_(cur)100.0−abs(pcl_(cur)−pcl_(ref))*mif_(ref)  (Equation 5)where pif_(cur) =peak index factor of the current fingerprint andpcl_(cur)=peak count location of the current fingerprint.

In step 1242, the current peak relative distance factor as comparedagainst the reference (prd_(ref)) is calculated, which is expressed asprf_(cur)=min(100.0,(prd_(cur)−1.0)/prd_(ref))*100.0)  (Equation 6)where prf_(cur)=peak relative factor of the current fingerprint andprd_(cur)=peak relative distance to the left side average of the currentfingerprint.

In step 1244, the current right relative factor is calculated, which isexpressed asrrf_(cur)=((rrd_(cur)−1.0)/rrd_(ref))*100.0  (Equation 7)where rrf_(cur)=right relative factor of the current fingerprint andrrd_(cur)=right relative distance to the left side average of thecurrent fingerprint.

Referring again to FIG. 12A, in step 1210, the overall score can now becalculated as:score=(PIW*pif_(cur))+(PRD*prf_(cur))+(RRD*rrf_(cur))  (Equation 8)

As described previously, the fingerprint matching process calculates ascore for each increment of an uncertainty region. When the processcompletes the uncertainty region, the scores are ranked and a list ofcandidates is provided to a user. The ranking may use any criteria, butthe scores are ranked with the highest score listed first for purposesof example.

Referring to FIGS. 13A-13C, an embodiment of a process for searching fora reference fingerprint in an uncertainty region is illustratedvisually. It is understood that FIGS. 13A-13C are not necessarily drawnto scale, but are provided to visually illustrate the overall process ofcomparing candidate fingerprints against reference fingerprints.

A reference waveform representation 1300 (FIG. 13A) is broken down intobasic elements that form a reference fingerprint 1302 (FIG. 13B). Asdescribed with respect to FIG. 6, the reference fingerprint 1302 may bebroken down into particular parts, such as a width 1304, a left sideaverage 1306, a right side average 1308, and a peak 1310 that has heightand index attributes. These parts and corresponding calculations havebeen described in detail above and are not described in the presentexample.

As illustrated in FIG. 13B, from a visual perspective, the left sideaverage 1306 is relatively high compared to the right side average 1308.The peak index is approximately at the midpoint of the width 1304. Thesecomponents describe the reference fingerprint 1302 for which anuncertainty region will be scanned.

As illustrated in FIG. 13C, a waveform 1312 (e.g., from a gamma log)falls within an uncertainty region 1314. The width of the uncertaintyregion 1314 is greater than the width of the reference fingerprint 1302and so multiple search windows will be scanned to try to identify thereference fingerprint 1302. In the present example, the search windowsbegin with a search window 1316 at depth “1”, include a search window1318 at depth “2” and a search window 1320 at depth “m”, and end with asearch window 1322 at depth “n”. Other search windows may be includedbased on the size of the uncertainty region and the width of thereference fingerprint 1302. It is understood that the depth may be theactual depth (e.g., 7232 feet) or may be an index based on theuncertainty region 1314 (e.g., the first search window in theuncertainty region) or another baseline.

As illustrated in FIG. 13D, the search window 1316 corresponds to acandidate fingerprint 1324, the search window 1318 corresponds to acandidate fingerprint 1326, the search window 1320 corresponds to acandidate fingerprint 1328, and the search window 1322 corresponds to acandidate fingerprint 1330.

From a visual perspective, the candidate fingerprint 1324 has a leftside average that is relatively long compared to the right side average.Furthermore, the right side average is higher than the left sideaverage. The peak is relatively low and the peak index is shiftedtowards the right side. When compared to the reference fingerprint 1302,the differences are significant. For purposes of example, the candidatefingerprint 1324 is assigned a score of ten out of one hundred.

The candidate fingerprint 1326 has a left side average that isrelatively long compared to the right side average, but shorter thanthat of the candidate fingerprint 1324. The right side average is higherthan the left side average. The peak is relatively low and peak index isshifted towards the right side, but less than the shift in the candidatefingerprint 1324. When compared to the reference fingerprint 1302, thedifferences are significant. For purposes of example, the candidatefingerprint 1326 is assigned a score of fifteen.

The candidate fingerprint 1328 has a left side average that isrelatively equal in length to the right side average. The right sideaverage is significantly lower than the left side average. The peak ishigher than the peaks of the candidate fingerprints 1324 and 1326 and isrelatively centered. When compared to the reference fingerprint 1302,the similarities are significant. For purposes of example, the candidatefingerprint 1328 is assigned a score of ninety-five.

The candidate fingerprint 1330 has a left side average that is shortcompared to the right side average. The right side average issignificantly lower than the left side average. The peak is lower thanthe peak of the candidate fingerprint 1328 and similar to the peaks ofthe candidate fingerprints 1324 and 1326. The peak index is relativelyfar to the left. When compared to the reference fingerprint 1302, thesimilarities are significant, although less significant than those ofthe candidate fingerprint 1328. For purposes of example, the candidatefingerprint 1330 is assigned a score of eighty.

For purposes of example, all other scores for candidate fingerprintswithin the uncertainty region 1314 are less than eighty and greater thanfifteen. The scores may be sent as a ranked candidate list as shown inTable 1 below with a higher score indicating a better match.

TABLE 1 Candidate list Depth Score m 95 n 80 2 15 1 10

Referring to FIG. 14, one embodiment of a GUI 1400 illustrates aninterface that may be used to provide reporting information on apossible match and to present options for modifying the drilling plan.It is understood that the GUI 1400 is for purposes of example and thatmany different GUIs may be used to provide some or all of thefunctionality shown with the GUI 1400. In the present example, the GUI1400 includes a results panel 1402 that may stand alone or may be partof another GUI.

In the present example, a potential match 1404 for Planned Marker 5(e.g., marker 1022 of FIG. 10) has been identified with ninety-fourpercent of the conditions for a match being met. Information from thelog may be provided, including measured depth (MD), TVD, inclination(INC), and vertical section. Continuing the example of FIG. 5, theplanned marker 1022 had an estimated depth of 8179 feet and estimatedvertical section 515. As reported from the log, the possible match 1404has a TVD of 8193 feet. Accordingly, while at the correct TVD, thepossible match is fourteen feet lower than the plan.

The results panel 1402 may present a user with various options,including options 1406, 1408, and 1410. Option 1406 is to continuesearching for the next marker without any changes. Option 1408 is tocontinue to the next marker, but with a change in dip as defined in textbox 1412. Option 1410 is to continue to the next marker, but with anadjustment to the next planned marker's estimated TVD as defined in textbox 1414. In the current example, option 1410 has been selected and theestimated TVD for the next marker (e.g., planned marker 6) will beadjusted downward by fourteen feet. It is understood that theadjustments of options 1408 and 1410 may affect the remainder of thedrilling plan or may be limited (e.g., may only affect a defined numberof markers).

It will be appreciated by those skilled in the art having the benefit ofthis disclosure that this system and method for formation detection andevaluation provides an improved process for assessing the accuracy of adrilling plan during drilling and for modifying the plan based on theassessment if needed. It should be understood that the drawings anddetailed description herein are to be regarded in an illustrative ratherthan a restrictive manner, and are not intended to be limiting to theparticular forms and examples disclosed. On the contrary, included areany further modifications, changes, rearrangements, substitutions,alternatives, design choices, and embodiments apparent to those ofordinary skill in the art, without departing from the spirit and scopehereof, as defined by the following claims. Thus, it is intended thatthe following claims be interpreted to embrace all such furthermodifications, changes, rearrangements, substitutions, alternatives,design choices, and embodiments.

What is claimed is:
 1. A method for using markers with a drilling plan,comprising: using, by a computer system, a first log file of a firstwell in order to identify and store one or more markers that have aname, a true vertical depth (TVD) and a waveform; monitoring in realtime, by the computer system, second well log data generated while asecond well is being drilled; comparing the second well log data to theone or more markers to locate a match to at least one marker in apredetermined TVD range; creating, by the computer system, at least oneplanned marker for the second well corresponding to a located matchwithin the one or more markers in the predetermined TVD range;assigning, by the computer system, an estimated TVD value and anuncertainty range value to each of the at least one planned marker; andreporting when a matching marker is located for one of the one or moremarkers in the predetermined TVD range.
 2. The method of claim 1,wherein the step of comparing further comprises correcting the secondwell log data to account for true vertical depth prior to comparison tothe at least one marker of the first well log file.
 3. The method ofclaim 1 further comprises the step of creating, by the computer system,each of the one or more planned markers with the assigned estimated TVDand the uncertainty range value.
 4. The method of claim 1, wherein thestep of monitoring further comprises monitoring the second well log datafrom a gamma log file.
 5. The method of claim 1, wherein the step ofmonitoring further comprises monitoring the second well log data todetect at least one of information regarding resistivity, porosity,pressure, neutron density, rate of penetration and mechanical specificenergy.
 6. The method of claim 1 further comprising adjusting, by thecomputer system, a dip angle of the drill plan between the first plannedmarker and a next sequential planned marker of the plurality of plannedmarkers based on the report.
 7. The method of claim 1 further comprisingadjusting, by the computer system, the estimated TVD of comparison for anext marker based on the report.
 8. The method of claim 1, wherein thestep of reporting further comprises the step of generating an indicationthat the identified plan marker matches the corresponding identified andstored marker.
 9. The method of claim 8, wherein the indication that theidentified plan marker matches the corresponding identified and storedmarker is forwarded for corrective action in real time.
 10. The methodof claim 1, wherein the comparing further comprises: creating, by thecomputer system, at least one fingerprint of the at least one markerwithin the predetermined TVD range; and determining, by the a computersystem, whether the at least one fingerprint matches a waveformrepresentation of the second well log data.
 11. The method of claim 10,wherein the determining further comprises: comparing, by the computersystem, a left side average of the fingerprint with a left side averageof the waveform representation of the second well log data; comparing,by the computer system, a right side average of the at least onefingerprint with a right side average of the waveform representation ofthe second well log data; comparing, by the computer system, a peakheight of the at least one fingerprint with a peak height of thewaveform representation of the second well log data; comparing, by thecomputer system, a peak location of the at least one fingerprint with apeak location of the waveform representation of the second well logdata; and calculating, by the computer system, a score based on the atleast one comparisons of the left side averages, the right sideaverages, the peak heights, and the at least one peak locations.
 12. Asystem, comprising: a network interface; a processor coupled to thenetwork interface; a memory coupled to the processor and configured tostore a plurality of instructions executable by the processor, theinstructions including instructions for: using, by a computer system, afirst log file of a first well in order to identify and store one ormore markers that have a name, a true vertical depth (TVD) and awaveform; monitoring in real time, by the computer system, second welllog data generated while a second well is being drilled; comparing thesecond well log data to the one or more markers to locate a match to atleast one marker in a predetermined TVD range; creating, by the computersystem, at least one planned marker for the second well corresponding toa located match within the one or more markers in the predetermined TVDrange; assigning, by the computer system, an estimated TVD value and anuncertainty range value to each of the at least one planned marker; andreporting when a matching marker is located for one of the one or moremarkers in the predetermined TVD range.
 13. The system of claim 12,wherein the instructions for the step of comparing further comprisesinstructions for correcting the second well log data to account for truevertical depth prior to comparison to the at least one marker of thefirst well log file.
 14. The system of claim 12 wherein the instructionsfurther comprise instructions for storing, by the computer system, eachof the one or more planned markers with the assigned estimated TVD andthe uncertainty range value.
 15. The system of claim 12, wherein theinstructions for the step of monitoring further comprise instructionsfor monitoring the second well log data from a gamma log file.
 16. Thesystem of claim 12 wherein the instructions for the step of monitoringfurther comprise instructions for monitoring the second well log data todetect at least one of information regarding resistivity, porosity,pressure, neutron density, rate of penetration and mechanical specificenergy.
 17. The system of claim 12, wherein the instructions furthercomprise instructions for adjusting, by the computer system, a dip angleof the drill plan between the first planned marker and a next sequentialplanned marker of the plurality of planned markers based on the report.18. The system of claim 12, wherein the instructions further compriseinstructions for adjusting, by the computer system, the estimated TVD ofa next marker based on the report.
 19. The system of claim 12 whereinthe instructions for the step of reporting further comprise instructionsfor generating an indication that the identified plan marker matches thecorresponding identified and stored marker.
 20. The system of claim 19wherein the indication that the identified plan marker matches thecorresponding identified and stored marker is forwarded for correctiveaction in real time.
 21. The system of claim 12, wherein theinstructions for scanning further comprise instructions for: creating,by the computer system, at least one fingerprint of the at least onemarker within the predetermined TVD range; and determining, by the acomputer system, whether the at least one fingerprint matches a waveformrepresentation of the second well log data.
 22. The system of claim 21,wherein the instructions for determining further comprise instructionsfor: comparing, by the computer system, a left side average of thefingerprint with a left side average of the waveform representation ofthe second well log data; comparing, by the computer system, a rightside average of the at least one fingerprint with a right side averageof the waveform representation of the second well log data; comparing,by the computer system, a peak height of the at least one fingerprintwith a peak height of the waveform representation of the second well logdata; comparing, by the computer system, a peak location of the at leastone fingerprint with a peak location of the waveform representation ofthe second well log data; and calculating, by the computer system, ascore based on the at least one comparisons of the left side averages,the right side averages, the peak heights, and the at least one peaklocations.
 23. A method for using one or more planned markers with adrilling plan, comprising: using, by a computer system, a first log fileof a first well in order to identify and store one or more markers thathave a name, a true vertical depth (TVD) and a waveform; monitoring inreal time, by the computer system, second well log data generated whilea second well is being drilled; comparing the second well log data tothe one or more markers to locate a match to at least one marker in apredetermined TVD range; creating, by the computer system, at least oneplanned marker for the second well corresponding to a located matchwithin the one or more markers in the predetermined TVD range;assigning, by the computer system, an estimated TVD value and anuncertainty range value to each of the at least one planned marker;generating an indication that the identified plan marker matches thecorresponding identified and stored marker in the predetermined TVDrange as the determination is completed; and forwarding the indicationfor corrective action to the drilling plan responsive to the indication.24. The method of claim 23, wherein the step of monitoring furthercomprises monitoring the second well log data from a gamma log file. 25.The method of claim 23, wherein the step of identifying further compriseidentifying the planned marker from at least one of informationregarding resistivity, porosity, pressure, neutron density, rate ofpenetration and mechanical specific energy.
 26. The method of claim 23,wherein the step of comparing further comprises correcting the secondwell log data to account for true vertical depth prior to comparison tothe at least one marker of the first well log file.
 27. A system,comprising: a network interface; a processor coupled to the networkinterface; a memory coupled to the processor and configured to store aplurality of instructions executable by the processor, the instructionsincluding instructions for: using, by a computer system, a first logfile of a first well in order to identify and store one or more markersthat have a name, a true vertical depth (TVD) and a waveform; monitoringin real time, by the computer system, second well log data generatedwhile a second well is being drilled; comparing the second well log datato the one or more markers to locate a match to at least one marker in apredetermined TVD range; creating, by the computer system, at least oneplanned marker for the second well corresponding to a located matchwithin the one or more markers in the predetermined TVD range;assigning, by the computer system, an estimated TVD value and anuncertainty range value to each of the at least one planned marker;generating an indication that the identified plan marker matches thecorresponding identified and stored marker in the predetermined TVDrange as the determination is completed; and forwarding the indicationfor corrective action to the drilling plan responsive to the indication.28. The system of claim 27, wherein the instructions for the step ofmonitoring further comprise instructions for monitoring the second welllog data from a gamma log file.
 29. The system of claim 27, wherein theinstructions for the step of identifying further comprise instructionsfor identifying the planned marker from at least one of informationregarding resistivity, porosity, pressure, neutron density, rate ofpenetration and mechanical specific energy.
 30. The system of claim 27,wherein the instructions for the step of comparing further comprisesinstructions for correcting the second well log data to account for truevertical depth prior to comparison to the at least one marker of thefirst well log file.